Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Swamps, lakes and ditches.
Flowers: May-July
Origin: Native
Growth Duration: Perennial
Conservation Status: Not of concern
Pollination: Bees, flies
Erect, glabrous herbs from creeping rhizomes, the flowering stems 2-8 cm. tall, with fine, purplish-black spots almost throughout.
Lowermost leaves sessile and greatly reduced; upper leaves opposite, nearly sessile, linear-lanceolate to narrowly elliptic, long-acuminate, up to 15 cm. long, narrowed gradually to the base.
Flowers crowded and sub-sessile in dense, slender, pedunculate racemes in the axils of 2 or 3 pairs of larger leaves near mid-stem; calyx lobes 5, united only at the base, spotted, glabrous, lanceolate, 2-3 mm. long; corolla divided nearly to the base, the 5 lobes linear-lanceolate, pale yellow, twice the length of the calyx; stamens 5, exerted, opposite the corolla lobes, the filaments distinct, glabrous.
Capsule 2.5 mm. long, spotted, opening by 5 valves.
PNW Herbaria: Specimen records of Lysimachia thyrsiflora in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Lysimachia thyrsiflora checklist entry
OregonFlora: Lysimachia thyrsiflora information
E-Flora BC: Lysimachia thyrsiflora atlas page
CalPhotos: Lysimachia thyrsiflora photos